Axios

The billionaires pouring money into rockets don't appear, at least so far, to be focused entirely on money. Instead, they are turning childhood love of sci-fi into a private space exploration companies. Elon Musk has SpaceX, Richard Branson has Virgin Galactic and Microsoft co-founder Paul Allen has Stratolaunch.

The big picture: Jeff Bezos is much richer than all of them put together, which means he's been able to worry less than any about profits, shareholders or commercial contracts.

After an absence lasting 9 years, the U.S. is seeking to resume launching humans to space from American soil.

But this time it won’t be NASA doing the launches — it will be Boeing and SpaceX, private contractors that NASA selected to transport crew to the International Space Station.

This visualization shows the 18,120 objects being tracked in low-Earth orbit by the U.S. military's Joint Space Operations Center — including nearly 13,000 that are classified as space debris.

Why it matters: As space opens up to more nations, companies and possibly nonprofits, concerns are growing about how to track and reduce debris that threatens satellites and spacecraft.

Cheaper rocket launches and better technology may make satellites a more viable option for delivering fast, affordable consumer broadband services around the world.

The big picture: For nearly 30 years, satellites have been used to beam high-speed internet service to rural areas that are hard to reach with terrestrial networks. But that's often a last-resort option due to the limitations of the technology, including connection lag, spotty service, and lower bandwidth.

Some experts are skeptical that space will become a trillion-dollar industry, and a bubble may already be forming in the current space economy.

The billionaires tend to steal the space show. But behind them are about 40 other rocket companies looking to capture — and build more demand for —the market to launch small satellites and other payloads.

In the new century, China has joined the U.S. and Russia as a top competitor in the space race. Here's an interactive look at the government, military, commercial and civil satellites each contender has launched.

Astronomers have confirmed the existence of more than 3,000 "exoplanets" — planets that aren't in our solar system, orbiting stars other than our sun. The chart above shows how similar they are to Earth.

Why it matters: A small number of discovered exoplanets — those that are small enough to have a rocky surface and the right distance from their star to hold liquid water — may be able to support life, and provide clues about the evolution of our own planet.